Windmill accelerator



June 25, 1929. MA 1,718,869

WINDMILL ACCELERATOR Filed Sept. 20, 1926 2 Sheets-Sheet 1 June 25, 1929.

' F. S. NIAS YIINDMILL ACCELERATOR Filed Sept. 20 1926 2 Sheets-Sheet 2 l 'atented June 25, 1929.

UNITED STATES PATENT OFFICE.

"WINDMILL ACCELERATOR.

Ap lication filed September 20, 1926, Serial No. 136,480, and in Great Britain October 20, 1925.

windmill blades and along the trailing edges thereoi. The members oit each series ot auxiliary blades will thus be in parallelism with their edges disposed at an incline with respect to the edges of the windmill blade carrying them.

To enable the invention to be fully understood I will describe it by reference to the accompanying drawing, in which Figures 1 and 2 are, respectively, a front elevation and a side elevation of the sails of a windmill provided with accelerator blades in accordance with the invention.

Figure 3 is a section on the line 3-45, Figure l.

a, a, a, a are the windmill sails or blades radiating from the boss or hub b and inclined with respect to their common plane in the usual. way so that they will be caused to rotate in the said plane by the action of the wind on their front faces in a direction normal to the said plane.

0, 0 are the auxiliary or accelerator blades which. I apply to the active or working faces of the sails (1/, at a common inclination thercto, these accelerator blades being made of rectangular flat plates and applied in series along one edge, and preferably the trailing edge of each sail a. The members of each series of blades 0 are in parallelism, with their edges inc-lined with respect to the edges of the sail a carrying them. In the drawing, the longitudinal edges of each series of accelerator blades 0 are at a common inclination of about 30 to the trailing edge of the sail a on which theyare mounted, as indicated in Figure. 1, whilst the said blades have a common inclination, as shown clearly in Figure 3, oi: about to the said sail.

I do not restrict myself to the said angles of inclination as they may be varied in accordance with requirements and the varying angles of the sails with respect to the direction. oi the wind.

Claims:

1. A windmill sail comprising a of propeller blades mounted upon a hub for rotation therewith, and a plurality of parallel auxiliary blades mounted upon the windward lace oi each propeller blade near its trailing edge, said auxiliary blades projecting forwardly from the windward faces of the propeller blades.

2. In combination with a windmill sail comprising a set of propeller blades mounted upon a hub for rotation therewith, each blade having a plane windward taco, of a plurality of auxiliary blades mounted upon the trailing edge portion of the windward face of each n'opellor blade.

3. In combination with a windmill sail comprising a set of propeller blades mounted upon a hub for rotation therewith, ot' a plurality of auxiliary overlapping parallel blades mounted upon the trailing ed ge oi? the windward side of each propeller blade, said auxiliary blades forming acute angles with said trailing edges.

4. A sail of the wind wheel type comp rising a set of plane propeller blades, each blade being provided with a set (it plane auxiliary blades upon the trailing edge oat its windward side.

5. A fan shaped wheel comprising a set of plane blades mounted upon a hub for rotation therewith, each blade being inclined to present a surface for impact with air, and a series of parallel. overlapping plane auxiliary blades secured on said impact surface of each oi: said main blades near the trailing edge thereof.

FREDERICK SOMERSET NIAS. 

